Impaired induction of long‐term potentiation‐like plasticity in patients with high‐functioning autism and Asperger syndrome

Aim We aimed to investigate the induction of long‐term potentiation (LTP)‐like plasticity by paired associative stimulation (PAS) in patients with high‐functioning autism and Asperger syndrome (HFA/AS). Method PAS with an interstimulus interval between electrical and transcranial magnetic stimulation of 25 ms (PAS₂₅) was performed in patients with HFA/AS (n=9; eight males, one female; mean age 17y 11mo, SD 4y 5mo) and in typically developing age‐matched volunteers (n=9; five males, four females; mean age 22y 4mo, SD 5y 2mo). The amplitude of motor‐evoked potentials was measured before PAS₂₅, immediately after stimulation, and 30 minutes and 60 minutes later. A PAS protocol adapted to individual N20 latency (PAS_N20+2) was performed in six additional patients with HFA/AS. Short‐interval intracortical inhibition was measured using paired‐pulse stimulation. Results In contrast to the typically developing participants, the patients with HFA/AS did not show a significant increase in motor‐evoked potentials after PAS₂₅. This finding could also be demonstrated after adaptation for N20 latency. Short‐interval intracortical inhibition of patients with HFA/AS was normal compared with the comparison group and did not correlate with PAS effect. Interpretation Our results show a significant impairment of LTP‐like plasticity induced by PAS in individuals with HFA/AS compared with typically developing participants. This finding is in accordance with results from animal studies as well as human studies. Impaired LTP‐like plasticity in patients with HFA/AS points towards reduced excitatory synaptic connectivity and deficits in sensory‐motor integration in these patients.     

Use of Context in Pragmatic Language Comprehension by Children with Asperger Syndrome or High-Functioning Autism

Utilizing relevance theory, this study investigated the ability of children with Asperger syndrome (AS) and high-functioning autism (HFA) to use context when answering questions and when giving explanations for their correct answers. Three groups participated in this study: younger AS/HFA group (age 7–9, n = 16), older AS/HFA group (age 10–12, n = 23) and a normally functioning control group (age 7–9, n = 23). The results indicated that the younger AS/HFA group did less well when answering contextually demanding questions compared to the control group, and the performance of the older AS/HFA group fell in between the younger AS/HFA group and the control group. Both AS/HFA groups had difficulties explaining their correct answers, suggesting that they are not always aware of how they have derived answers from the context.     

Facial emotion recognition and visual search strategies of children with high functioning autism and Asperger syndrome

Adults with high functioning autism (HFA) and Asperger syndrome (AS) are often less able to identify facially expressed emotions than their matched controls. However, results regarding emotion recognition abilities in children with HFA/AS remain equivocal. Emotion recognition ability and visual search strategies of 26 children with HFA/AS and matched controls were compared. An eye tracker measured the number of fixations and fixation durations as participants were shown 12 pairs of slides, displaying photos of faces expressing anger, happiness or surprise. The first slide of each pair showed a face broken up into puzzle pieces. The eyes in half of the puzzle piece slides were bisected, while those in the remaining half were whole. Participants then identified which of three alternative faces was expressing the same emotion shown in the preceding puzzle piece slide. No differences between the participant groups were found for either emotion recognition ability or number of fixations. Both groups fixated more often on the eyes and performed better when the eyes were whole, suggesting that both children with HFA/AS and controls consider the eyes to be the most important source of information during emotion recognition. Fixation durations were longer in the group with HFA/AS, which indicates that while children with HFA/AS may be able to accurately recognise emotions, they find the task more demanding.     

Differential activation of the amygdala and the 'social brain' during fearful face-processing in Asperger Syndrome

Impaired social cognition is a core feature of autism. There is much evidence showing people with autism use a different cognitive style than controls for face-processing. We tested if people with autism would show differential activation of social brain areas during a face-processing task. Thirteen adults with high-functioning autism or Asperger Syndrome (HFA/AS) and 13 matched controls. We used fMRI to investigate 'social brain' activity during perception of fearful faces. We employed stimuli known to reliably activate the amygdala and other social brain areas, and ROI analyses to investigate brain areas responding to facial threat as well as those showing a linear response to varying threat intensities. We predicted: (1) the HFA/AS group would show differential activation (as opposed to merely deficits) of the social brain compared to controls and (2) that social brain areas would respond to varied intensity of fear in the control group, but not the HFA/AS group. Both predictions were confirmed. The controls showed greater activation in the left amygdala and left orbito-frontal cortex, while the HFA/AS group showed greater activation in the anterior cingulate gyrus and superior temporal cortex. The control group also showed varying responses in social brain areas to varying intensities of fearful expression, including differential activations in the left and right amygdala. This response in the social brain was absent in the HFA/AS group. HFA/AS are associated with different patterns of activation of social brain areas during fearful emotion processing, and the absence in the HFA/AS brain of a response to varying emotional intensity.     

Repetitive Behavior Profiles in Asperger Syndrome and High-Functioning Autism

Although repetitive behaviors are a core diagnostic domain for autism spectrum disorders, research in this area has been neglected. This study had two major aims (1) to provide a detailed characterization of repetitive behaviors in individuals with Asperger Syndrome (AS), high-functioning autism (HFA), and typically developing controls (TD); and (2) to examine whether differences in repetitive behavior profiles could provide evidence for the external validity of AS separate from HFA. Specifically, it was hypothesized that circumscribed interests would be more prevalent and cause more impairment in the AS group than the HFA group, while the reverse would be true for other categories of repetitive behavior. The parent(s) of 61 children and adolescents (19 with AS, 21 with HFA, and 21 TD) completed two interviews focused specifically on lifetime and current repetitive behavior symptoms. No reliable differences in repetitive behavior between AS and HFA children were found. Results suggested that circumscribed interests differ in developmental course from the three other DSM-IV-TR categories of repetitive behavior. Internal consistency among the four DSM-IV-TR categories of repetitive behavior was high, =.84, providing evidence for a unitary repetitive behaviors factor. The importance of expanding research in the repetitive behavior domain is highlighted as part of the necessary integration of behavioral and neurobiological approaches to understanding the etiology of autism.     

The Autism-Spectrum Quotient (AQ)—Adolescent Version

The Autism Spectrum Quotient (AQ) quantifies autistic traits in adults. This paper adapted the AQ for children (age 9.8–15.4 years). Three groups of participants were assessed: Group 1: n=52 adolescents with Asperger Syndrome (AS) or high-functioning autism (HFA); Group 2: n=79 adolescents with classic autism; and Group 3, n=50 controls. The adolescents with AS/HFA did not differ significantly from the adolescents with autism but both clinical groups scored higher than controls. Approximately 90% of the adolescents with AS/HFA and autism scored 30+, vs. none of the controls. Among the controls, boys scored higher than girls. The AQ can rapidly quantify where an adolescent is situated on the continuum from autism to normality.     

Cognitive and symptom profiles in Asperger's syndrome and high-functioning autism

Asperger syndrome (AS) and autistic disorder are two subtypes of pervasive developmental disorders (PDD), but there has been considerable debate over whether AS and autistic disorder without mental retardation (IQ > or = 70), called high-functioning autism (HFA), are distinct conditions or not. The aim of the present paper was to clarify this issue through a comparison of cognitive function and autistic symptom profiles. Based on the DSM-IV and ICD-10 definitions of language acquisition, 36 age- and IQ-balanced subjects with AS (mean age, 12.8 years; mean full-scale IQ, 98.3) were compared with 37 subjects with HFA (mean age, 12.6 years; mean full-scale IQ, 94.6) on the Japanese version of the Wechsler Intelligence Scales and the Childhood Autism Rating Scale-Tokyo Version (CARS-TV). Compared with the HFA subjects, the AS subjects scored significantly higher on Verbal IQ, Vocabulary, and Comprehension, but scored significantly lower on Coding. Although the total CARS-TV score did not differ significantly between the two groups, AS subjects scored significantly lower (i.e. less abnormal) on Verbal communication and Non-verbal communication than did the HFA subjects. A history of normal language acquisition in early childhood could predict his/her better verbal ability in mid-childhood or later. Autistic cognitive characteristics shared by both AS and HFA subjects appear to support the validity of the current diagnostic classification of PDD.     

Superior nonverbal intelligence in children with high-functioning autism or Asperger's syndrome

Some early studies showed discordance in cognitive strengths and weaknesses in individuals with high-functioning autism (HFA) or Asperger's syndrome (AS). The present study administered the French version of Colored Raven's Progressive Matrices in 14 children with HFA/AS and in 26 chronological age matched peers with typical development. We found a trend of superior nonverbal performance in Raven's Test in our HFA/AS participants compared to controls, and this “superiority” achieved statistical significance in the HFA/AS subgroup with a FIQ ≥ 90. Superior fluid intelligence seemed to exist in individuals both with HFA and with AS. A complementary use of both the Raven's Test and the Wechsler Intelligence Scales seems to be important for exploring the domain-specific as well as multidimensional profiles in individuals with autism.     

Perception of Talker Age by Young Adults with High-Functioning Autism

People with high-functioning Autism (HFA) can accurately identify social categories from speech, but they have more difficulty connecting linguistic variation in the speech signal to social stereotypes associated with those categories. In the current study, the perception and evaluation of talker age by young adults with HFA was examined. The participants with HFA performed similarly to a typically-developing comparison group in age classification and estimation tasks. Moreover, the participants with HFA were able to differentiate among talkers of different ages in a language attitudes task and rated older talkers as more intelligent than younger talkers. These results suggest that people with HFA are able to make reasonable social judgments about talkers based on their speech, at least for familiar social categories and personally relevant social attitudes.     

Sleep Patterns in School-age Children with Asperger Syndrome or High-functioning Autism: A Follow-up Study

The course of sleep patterns over 2–3 years was compared between 16 school-age children with Asperger syndrome (AS) or high-functioning autism (HFA) and 16 age- and gender-matched typically developing children, using 1-week actigraphy at baseline and follow-up. At baseline (mean age 11.1 years), children with AS/HFA had longer sleep latency and lower sleep efficiency during school days, but earlier sleep start and sleep end during weekends. At follow-up (mean age 13.7 years), children with AS/HFA had longer night wakings and lower sleep efficiency during weekends than the controls. The overall change of sleep patterns, however, is similar in children with AS/HFA and typically developing controls over a 2 to 3-year period. There is one change in affiliation since the time of the study, namely, Hiie Allik has defended her thesis, and obtained a doctoral degree at the Karolinska Institutet, Stockholm, Sweden. Dr. Allik conducted this study in partial fulfilment of the requirements for a doctoral degree at the Karolinska Institutet, Stockholm, Sweden.     

Brief report: Thought disorder in asperger syndrome: Comparison with high-functioning autism

Asperger syndrome (AS) is a pervasive developmental disorder generally regarded as a variant of autism. While it has been included in the ICD-10 and DSM-IV as a distinct diagnostic entity, it is still unclear to what extent it differs from highfunctioning autism (HFA). Persons with HFA have been reported to show a variety of deficits of thought processes. Abnormalities such as poor reality testing, perceptual distortions, and areas of cognitive slippage have been described using the Rorschach inkblot test (Dykens, Volkmar, & Glick, 1991). Since AS has been conceptualized as a mild variant of autism, we hypothesized that persons with AS will have fewer abnormalities on the Rorschach test compared to persons with HFA. To test this hypothesis, we compared 12 subjects with AS (ICD-10, 10 male, mean age = 12.2±3.3 years, mean full-scale IQ = 99.6) with 8 subjects with HFA (ICD-10/DSM-III-R, 7 male, mean age = 12.2±3.8 years, mean fullscale IQ = 83.4) on the Rorschach test. AS subjects demonstrated a trend towards greater levels of disorganized thinking than the HFA group. They were also more likely to be classified as Introversive suggesting that AS subjects may have more complex inner lives involving elaborate fantasies. Also, AS subjects tended to be more focused on their internal experiences. However, overall, the Rorschach test was not found to differentiate the two diagnostic groups on the majority of structural variables. Implications of these findings are discussed with regard to the diagnostic validity of Asperger syndrome.     

Theory of mind, severity of autistic symptoms and parental correlates in children and adolescents with Asperger syndrome

This study addresses the theory of mind (ToM) ability of Asperger's syndrome/high-functioning autism (AS/HFA) children and their parents and the severity of the autistic symptoms. Fifty-three families, each consisting of a mother, father and a child, participated in this study (N=159). The 53 children in the sample included 25 children diagnosed with AS/HFA and 28 typically developing (TD) children. The Social Attribution Task (SAT) and tests assessing autistic symptoms were used. AS/HFA children had lower scores than TD children on three of the SAT indices (Person, ToM Affective, and Salience). Fathers of AS/HFA children did not have lower scores than fathers of TD children on the SAT task, whereas mothers of AS/HFA children had lower scores on the Person index, a pattern similar to seen in their children, suggesting a possible genetic contribution of mothers to ToM deficit in AS/HFA children.     

The French Version of the Autism-Spectrum Quotient in Adolescents: A Cross-Cultural Validation Study

We assessed the accuracy of the French version of the Autism Spectrum Quotient (AQ) in adolescents with Asperger syndrome (AS) and high-functioning autism (HFA) compared to healthy controls and adolescents with psychiatric disorders (PDs). Three groups of adolescents, aged 11–18, were assessed: 116 with AS/HFA (93 with IQ ≥ 85 and 20 with 70 ≤ IQ < 85), 39 with other PDs, and 199 healthy controls. The AS/HFA group scored significantly higher than the healthy control and PD groups. A cut-off score of 26 was used to differentiate the autism group from healthy controls with 0.89 sensitivity and 0.98 specificity. Scores did not vary by age or sex.     

Wisconsin card sorting test in children with temporal lobe epilepsy

To search for the origin of frontal lobe dysfunction identified by the Wisconsin card sorting test (WCST) in temporal lobe epilepsy (TLE) patients, we investigated the WCST performance among 19 children with TLE (with hippocampal atrophy (HA group N=12), without structural lesions (NSL group N=7)), 15 patients with frontal lobe epilepsy (FLE group), and age-matched normal controls (N group). The paired verbal association learning test (PVALT) and Benton visual retention test (BVRT) were also performed. HA group and FLE groups achieved significantly fewer categories and demonstrated more perseverative errors on the WCST than NSL and N groups. In addition, category achievement in WCST showed significant inverse correlation to age at the initial status convulsivus in the HA group (P<0.05). The achievement on PVALT and BVRT did not show any significant differences between HA and FLE groups (P>0.05). Thus, the frontal lobe dysfunction in the HA group is found to exist as early as 7 years old, when they seem to have only a short seizure history or to receive a little electrical interference from the temporal lobe focus to the frontal region. These facts would underscore the importance of prefrontal dysfunction persisting from the early insults and only becoming apparent after maturation of the prefrontal region in patients with mesial TLE.     

The Autism-Spectrum Quotient (AQ): Evidence from Asperger Syndrome/High-Functioning Autism, Malesand Females, Scientists and Mathematicians

Currently there are no brief, self-administered instruments for measuring the degree to which an adult with normal intelligence has the traits associated with the autistic spectrum. In this paper, we report on a new instrument to assess this: the Autism-Spectrum Quotient (AQ). Individuals score in the range 0–50. Four groups of subjects were assessed: Group 1: 58 adults with Asperger syndrome (AS) or high-functioning autism (HFA); Group 2: 174 randomly selected controls. Group 3: 840 students in Cambridge University; and Group 4: 16 winners of the UK Mathematics Olympiad. The adults with AS/HFA had a mean AQ score of 35.8 (SD = 6.5), significantly higher than Group 2 controls (M = 16.4, SD = 6.3). 80% of the adults with AS/HFA scored 32+, versus 2% of controls. Among the controls, men scored slightly but significantly higher than women. No women scored extremely highly (AQ score 34+) whereas 4% of men did so. Twice as many men (40%) as women (21%) scored at intermediate levels (AQ score 20+). Among the AS/HFA group, male and female scores did not differ significantly. The students in Cambridge University did not differ from the randomly selected control group, but scientists (including mathematicians) scored significantly higher than both humanities and social sciences students, confirming an earlier study that autistic conditions are associated with scientific skills. Within the sciences, mathematicians scored highest. This was replicated in Group 4, the Mathematics Olympiad winners scoring significantly higher than the male Cambridge humanities students. 6% of the student sample scored 327plus; on the AQ. On interview, 11 out of 11 of these met three or more DSM-IV criteria for AS/HFA, and all were studying sciences/mathematics, and 7 of the 11 met threshold on these criteria. Test—retest and interrater reliability of the AQ was good. The AQ is thus a valuable instrument for rapidly quantifying where any given individual is situated on the continuum from autism to normality. Its potential for screening for autism spectrum conditions in adults of normal intelligence remains to be fully explored.     

Social Anxiety in High-functioning Children and Adolescents with Autism and Asperger Syndrome

We examined social anxiety and internalizing symptoms using the Social Phobia and Anxiety Inventory for Children (SPAI-C), the Social Anxiety Scale for Children -Revised (SASC-R), and the Child Behavior Checklist (CBCL) in a sample of fifty-four high-functioning subjects with autism or Asperger syndrome (HFA/AS) (M = 11.2 ± 1.7 years) and 305 community subjects (M = 12.2 ± 2.2 years). Children and adolescents completed the SPAI-C and SASC-R, and their parents completed the CBCL Internalizing scale. Adolescents with HFA/AS scored higher than the community sample on all measures. Behavioural avoidance and evaluative social anxiety increased by age within the HFA/AS group, whereas behavioural avoidance decreased by age in control participants. Data support that HFA/AS in adolescents may be associated with clinically relevant social anxiety symptoms.     

Social attribution in children with high functioning autism and Asperger syndrome: An exploratory study in the Chinese setting

The present study aimed to examine social attribution in children with high-functioning autism (HFA) and Asperger's syndrome (AS). A sample of 20 boys (9 with HFA and 11 with AS) and 20 age-matched controls were recruited for this study. All participated in two tasks measuring social attribution ability, the conventional Social Attribution Task (SAT) and a modified version with animals rather than shapes (mSAT). They also completed a battery of neuropsychological tests. Compared to typically developing controls, children with autism spectrum disorders were impaired on some measures in both SATs. However, group differences in ‘theory-of-mind’ indices were only significant in the mSAT, with the ASD group performing more poorly than controls. In addition, the scores in person index of both versions of the SAT correlated with executive function in children with HFA/AS. The current study found the mSAT paradigm was especially sensitive to ToM difficulties in young Chinese children with HFA/AS. Social attribution in children with HFA/AS, unlike neurotypical children, was related to executive function ability, suggesting these psychological domains are not distinct in children with autism spectrum disorders.     

Is clumsiness a marker for Asperger syndrome?

ABSTRACT. Although Asperger syndrome (AS) has been included in the ICD-10 as a distinct category within the pervasive developmental disorders, it is still unclear to what extent it differs from normal-intelligence autism (high-functioning autism; HFA). Persons with AS are said to be particularly clumsy. To test the hypothesis that clumsiness can reliably distinguish AS from autism, the present authors compared 11 patients with AS (ICD-10; 10 males; mean age, 13–6 years; mean IQ, 98) with nine patients with HFA (ICD-10/DSM-III-R; eight males; mean age, 12–9 years; mean IQ, 84). Clumsiness was assessed by the Bruininks-Oseretsky test. Both groups showed problems with coordination and the distribution of standard scores was virtually identical. This suggests that motor clumsiness, as measured by tests of coordination, may not reliably distinguish AS from HFA. However, qualitative differences may occur between the two groups in the manner in which movements are performed. Further research with larger samples may elicit differences into the pattern of motor deficits that occur in autism and AS.     

Social Skills Training for Adolescents with Asperger Syndrome and High-Functioning Autism

The effectiveness of a social skills training group for adolescents with Asperger syndrome and high-functioning autism (AS/HFA) was evaluated. Parents of six groups of adolescents (n = 46, 61% male, mean age 14.6) completed questionnaires immediately before and after the 12-week group. Parents and adolescents were surveyed regarding their experience with the group. Significant pre- to post-treatment gains were found on measures of both social competence and problem behaviors associated with AS/HFA. Effect sizes ranged from .34 to .72. Adolescents reported more perceived skill improvements than did parents. Parent-reported improvement suggests that social skills learned in group sessions generalize to settings outside the treatment group. Larger, controlled studies of social skills training groups would be valuable.     

Defining the Intellectual Profile of Asperger Syndrome: Comparison with High-Functioning Autism

Asperger syndrome (AS) is a disorder of early childhood characterized by autistic social deficits, subtle communication impairment, and excessive isolated interests. There is no history of language delay or of mental retardation. Despite its increasing popularity as a distinct condition, its diagnostic validity remains uncertain. It is still unclear to what extent AS differs from autism with normal intelligence sometimes referred to as high-functioning autism (HFA). However, some reports have suggested that persons with AS possess a distinct profile on tests of intelligence characterized by a high verbal IQ and a low performance IQ, whereas in most cases with HFA, the pattern is reversed. Since few studies have directly compared AS subjects with HFA controls using unmodified diagnostic criteria and standardized measures of assessment, in this report we compared 22 AS subjects with 12 HFA controls, matched on age, sex and level of intelligence. As a group, subjects with AS showed a higher verbal IQ and higher scores on information and vocabulary subtests than those with HFA. However, scores of several AS and HFA subjects showed a mixed pattern. Implications of these findings are discussed in the context of the validity of Asperger Syndrome.